Thermal stresses applied on helicopter blades useful to retrieve defects by means of infrared thermography and speckle patterns

F. López, S. Sfarra, A. Chulkov, C. Ibarra-Castanedo, H. Zhang, M. A. Omar, V. Vavilov, X. P.V. Maldague

Research output: Contribution to journalArticle


This work presents a non-destructive analysis based on infrared thermography (IRT) and speckle inspection methods performed on a helicopter blade. In both cases, thermal stresses are needed in order to provoke the visualization of defects. The sample possess fabricated defects, and three techniques were selected, namely, long-pulse thermography, flash thermography, and digital speckle photography (DSP) to retrieve their positions. The first two techniques belong to the group of infrared imaging, that are inherent to the analysis of the infrared thermal patterns to detect internal anomalies in the material, whilst the last one corresponds to the optical imaging group that requires visible light to measure the material response under a thermal stimulus. The active approach, useful to produce a gradient in either, thermal and/or displacement field of the material, was used. In all cases, heat lamps were used to generate the required thermal stresses. Post-processing algorithms were applied to raw data in order to improve the defect detection. Results are finally compared to evaluate pros and cons of each method.

Original languageEnglish
Article number100511
JournalThermal Science and Engineering Progress
Publication statusPublished - 1 Aug 2020



  • Defect detection
  • Digital speckle photography
  • Flash and long-pulse heating
  • Helicopter blade
  • Infrared thermography
  • Speckle
  • Thermal stimulus

ASJC Scopus subject areas

  • Fluid Flow and Transfer Processes

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